A conventional position detecting apparatus provided with a display apparatus is described in Japanese Published Patent Application No. 2002-215317. The conventional position detecting apparatus is an electromagnetic induction system and is located at a back side of the display apparatus.
Additionally, Japanese Published Patent Application No. 11-110115 describes another conventional position detecting apparatus, which is an electrostatic coupling system, provided with a display apparatus. In order to decrease moiré generated when a detection conductor of the position detecting apparatus is provided on a display side of the display apparatus, detection electrodes of the electrostatic coupling system are typically formed on the display side as broken-line like detection electrodes.
When the electromagnetic induction system position detecting apparatus is used with the display apparatus, the position detecting apparatus is typically located at the back side of the display apparatus. On the other hand, when the electrostatic coupling system position detecting apparatus is used, the detection conductor (i.e., detection electrodes) of the position detecting apparatus is formed as a broken-line shape and is typically located at the display side of the display apparatus.
An apparatus that detects a designated position on a board called a “tablet/digitizer” and an input apparatus that inputs position information are widely used with computers. The tablet/digitizer uses the position detecting apparatus to detect the designated position. Although various technologies have been developed for detecting the position designated on the board, the position detecting apparatus that uses the electromagnetic induction system has been found extremely effective, because the electromagnetic induction system position detecting apparatus is high in detection accuracy and reliability.
Additionally, an apparatus in which a thin display apparatus (e.g., a liquid crystal display) and a tablet/digitizer are integrally formed as one body have been developed. In this case, a screen of the display apparatus is the surface of the board (i.e., the tablet/digitizer). When using the electromagnetic induction system position detecting apparatus, since the designated position of an indicating device can be detected even when the indicating device and the surface of the board are spaced apart, the position detecting apparatus is typically provided at the back side of the display apparatus.
However, when the position detecting apparatus is provided at the back side of the display apparatus, the position detecting apparatus restricts a design of the display apparatus and location of a driving circuit for the display apparatus located at the back side of the position detecting apparatus. That is, when the position detecting apparatus is attached to the back side of the display apparatus later on (e.g., after manufacturing the display apparatus and the driving circuit), a large number of conditions are imposed upon the design and specification of the display apparatus (e.g., the placement of the driving circuit on the display apparatus).
On the other hand, a detecting portion of the position detecting apparatus can be formed on a transparent substrate such that the transparent substrate is provided on the display side of the display apparatus. According to this arrangement, conditions and restrictions imposed upon the design and specification of the display apparatus can be minimized substantially. However, since the detecting portion of the electromagnetic induction system position detecting apparatus typically requires a large number of detecting conductors, when the position detecting apparatus is disposed on the display side of the display apparatus, a moiré pattern(s) occurs between an arrangement of display elements (e.g., pixels) of the display apparatus and the detecting conductors of the detecting portion. The moiré pattern(s) causes interference and viewing problems on the display apparatus.